Mayer started the two-year rotational training program to home-grow managers who would be "Googley." The program has since become rather legendary, and former Google CEO Eric Schmidt told Steven Levy that he expects an APM alumni to run the company someday.

When you pick people who are leaders and show the sort of entrepreneurial zeal that makes them a great fit at Google, you also pick people who are confident enough to leave Google to build their own companies.

And a lot have.

"We get two to four good years, and if 20 percent stay with the company, that's a good rate," Mayer told Newsweek in 2007. "Even if they leave it's still good for us. I'm sure that someone in this group is going to start a company that I will buy some day."

Brian Rakowski was Google's very first APM.

Rakowski is now Google's VP of product management focusing on Android. Suitably, Rakowski also now runs the APM program.

What's changed since Mayer left the program? Not much, according to Rakowski.

"One of the best things about the APM program is that so many incredible people have gone through the program over the last 11 years and want stay involved," he writes on Quora. "In the spirit of tapping into the alumni network, we've also started a APM speaker series where APM alumni who have gone on to do interesting things (at Google or outside) give a talk to the current APMs."

Jeff Bartelma left Google to join Dropbox.

Google+

Bartelma studied engineering at MIT before joining the APM program, where he worked on product search. He eventually left Google to be the director of product at Dropbox in 2010.

Si Shen cofounded PapayaMobile in 2008.

Twitter

Shen spent four years at Google working on Android development and marketing and then Maps before founding Beijing-based mobile gaming company PapayaMobile in 2008. PapayaMobile created over 13 games, and then shifted to start making its mobile game engine available to other social game developers. According to its website, the company has over 1,000 titles connecting to its network.

Interestingly, Shen also appeared on a popular Chinese dating reality show in 2012, which helped her company become more widely recognized, according to Women of China.

Bret Taylor runs a collaborative productivity startup called Quip.

Bret Taylor, co-founder of Quip Quip

Taylor has an impressive track record. He quit Google, where he led the creation of Google Maps, to found a startup called FriendFeed that Facebook eventually bought for roughly $50 million. Taylor then served as Facebook's CTO for about three years before leaving to found Quip.

Nick Baum founded a company called StoryWorth that helps people record personal family stories.

Nick Baum

Baum worked at Google for roughly five years before leaving the company to work on a startup called WhereBerry that helped people plan outings with their friends. After WhereBerry failed to gain traction, he started StoryWorth.

StoryWorth brings families closer through story sharing. Once a week, the company sends an evocative prompt question to participants and then stores their answers.

"I love the idea that a hundred years from now, millions of people would have their great-grandparent’s full life story," Baum tells Business Insider.

Daniel Demetri got poached by a financial startup called Earnest.

Daniel Demetri

Demetri worked at Google for a little over three years before a small startup called Earnest poached him to be a product manager. Earnest gives out super-low-interest loans to financially responsible young people.

After spending three years at Google working on its communication and collaboration products (like the initial prototype for Gchat), Rosenstein ditched for a lead engineering position at Facebook. He spent almost two years there before teaming up with FB's founder, Dustin Moskovitz, to create Asana.

Major companies like Twitter, Foursquare, Uber, Airbnb, Pinterest, and Dropbox all use the company's tools. Rosenstein also founded One Project, which aims to get the world's technologists focused on global problems together.

Clav Bavor still works at Google as a VP of product.

Bavor has been with Google since 2005. He tackles product management and user experience design for Google Apps for business and education, Google Drive, Google Docs, and Gmail, including the company's new app to reinvent email. He also helped design Google Cardboard, the company's simple virtual reality device.

Ben Lewis sold not one, but two startups to Facebook

After Lewis sold his company Tapjoy to Facebook for an undisclosed amount, he started Karma, a social commerce company that let users give gifts from their phones. Facebook bought that, too, and then shut the app down.

Harry Glaser works at a data visualization startup called Periscope with a few other Xooglers.

"Harry handles Periscope's customer support, sales, office hunting, whiskey buying, and website copy writing. In his spare time he still checks in a little code, much to the annoyance of the other engineers."

Alex Collins quit his comfy Google job to be a musician.

Alex Collins / SoundCloud

Alex Collins worked at Google for four years, most recently for the search ads team, before taking a big risk to quit his comfortable, well-salaried job to make music.

Jamie Davidson sold his startup PrimaTable and now works at Redpoint Ventures.

Davidson left Google to found a reservations startup called PrimaTable, which eventually sold to HotelTonight. Davidson was the VP of product at HotelTonight for a little while before joining Redpoint Ventures as a senior associate.